89 colony park idles like garbage please help.

[Colony Park]

Just bought an 89 colony park 5.0 EFI and this last week has been absolute nightmare. When I got it it wouldn't start. Replaced ECM and fixed some wiring issues. Now it runs but it will not idle. It burns extremely Rich and runs rough. It drives along ok. Check engine light is on and occasionally it will flash off and car will miss for a split second. Codes are 21 22 24 34. The coolant temp sensor tests within spec and has no response when I jumper the harness. The map sensor is unresponsive as well, tests ok, have 5v reference and ground and output. If I unplug the fuel pump relay while it's running it will smooth out and run fine for 15 seconds or so before it stalls from lack of fuel. I thought maybe a bad fuel pressure regulator but it seems fine, it appears to be responsive to vacuum and I can hear gas dribble back into tank after I shut car off... Iac seems fine... Newish plugs and wires... Had old shitty gas in it but I drained most of it out and put some high test in it. Am I missing something? Could a bad o2 sensor cause this? Egr didn't seem stuck but I haven't disassembled it. Please help I'm so confused. Fuel injection sucks

[nfldfordltd]

Might be a long shot, but try changing your fuel filter if you haven't already. ECM might be in "limp mode" too where it was disturbed and replaced/repaired. Also check TP sensor for proper operation. Hope this helps.

[Colony Park]

Ya has new filter on it already and tp sensor seems to move in smooth increments but I'm not sure what spec is.... What is limp mode? How do I get it out of limp mode? New ECM has same numbers as old one...

[gadget73]

Is the vacuum line to the MAP sensor in good shape? Does it run better with the MAP unhooked? If no vacuum, fix that. If it runs better with the MAP unhooked, replace the MAP. For some reason those seem to fail in a way that makes the engine run just like the MAP vac line is unhooked, but it usually seems to run better if you unhook the vac line.


These don't have limp mode. Its not quite that advanced.

[91waggin]

89 colony park idles like garbage please help.

You got 21 because the engine wasn't warmed up when you did self test. 24 probably same thing. Don't worry about 34 for now. 22 bothers me and with the rich problem definitely makes me think you have a problem with the MAP. I had the same issue where the car wouldn't even run, just sputter and stall and would smell pig rich. Replaced MAP and vacuum line and all was good.

I know you say you tested MAP but without an oscilloscope you can't actually test it because it produces a waveform, not 0-5v like the GM units. Inspect the vacuum line and you should almost definitely replace the MAP.

Your problem is running rich, not lean, so we can rule out fuel filter. If it was clogged it would starve the engine for fuel, not dump fuel in, so that's not it. O2 sensors aren't used at idle and are only used at cruise for minor fuel trim adjustments, so we can ignore those. And Thain is right, there is no limp home mode that can be turned on or off.

Last piece of advice--the battery must be disconnected for a few minutes (drink a beer) after changing any fuel injection sensor so the computer can relearn the new sensor, whatever it is. Otherwise it's trying to use old adaptive values for the new sensor, instead of relearning the new one.

[mobydick]

+1 on the map. I had an idling problem with my wagon. It was a bad map and the vacuum line running to it was shot as well.

[miamibob]

"Last piece of advice--the battery must be disconnected for a few minutes (drink a beer) after changing any fuel injection sensor so the computer can relearn the new sensor, whatever it is. Otherwise it's trying to use old adaptive values for the new sensor, instead of relearning the new one."

Would it not relearn after "x" amount of restarts??

[P72Crazy]

I love this site. You guys just jump in to help a fellow out when every goes nuts! I have had problems numerous fuel delivery issues with my 5.8 VV equipped cars. In fooling around trying to get the parked cars running, I have "glazed" many spark plugs by dumping fuel down the carb to crank them. Too rich on the spark plugs will glaze them quickly and actually cause the car to run like crap or not even crank. As you also know, I've been plagued by rust in the tanks of my cars that where parked so don't discount rust in the fuel system! Ford fuel tanks rust from the inside-out !

[91waggin]

"Last piece of advice--the battery must be disconnected for a few minutes (drink a beer) after changing any fuel injection sensor so the computer can relearn the new sensor, whatever it is. Otherwise it's trying to use old adaptive values for the new sensor, instead of relearning the new one."

Would it not relearn after "x" amount of restarts??

Yes it does learn after a lot of restarts, but it learns much quicker if you disconnect the battery. If you disconnect the battery you're starting with a blank slate instead of having to unlearn the old sensor's adaptive values before learning the new one.